I don't know for sure if your changes will be overwritten, but most likely they will, it's never a good idea editing episervers own files.
A better aproach would be to create your own elements that extends the built in ones. Take a look here(Extendable/Customizable). As the article points out, everything is just blocks so you could do pretty much whatever you want :)
You might also want to check out this post by Alf Nilsson where he shows how you can extend the rendering and also how you can extend the different element types.
Yeah you are right, I just realised i missed the simple fact that i can just copy the markup for the default models and create my own views that i then modify. In a update whipe scenario all i have to do is delete the new default views for the default models again.
Now i just have to find out how to remove some of the default elements from the element list that i dont want to be visible:)
For overriding built-in Element's view template without being overrided by upgrade process, you can put your view template into separated folder, see article here and here
For disable/hide built-in Elements, just go to adminMode/ContentType, choose the BlockType and uncheck "Available in Edit view".
Form and FormElement are just Episerver Blocks.
I have been working with learning episerver forms and how to go about it. As it is now i have used the default views in modules/_protected/EPiServer.Forms/Views and changed them a bit with different style rules and markup.
I have also created my own element and instead of using a shared folder for the view i have put it in the same place where all the default ascx views are. Also i added an image where the other contenttype images are located inside the epi-forms/themes/sleek/images folder.
My question is, will future updates wipe all markup changes i made in the views folder meaning that i have to rely on the default markup and name of style classes already in place if i want to use the default elements and container?
Bonus question: Is there any way i can remove/hide properties on default elements and if not is there a way to remove/hide a default element from the list of elements in edit mode?
Best regards Jonas.C